不修改数组找出重复的数字-golang

func duplicateInArray(nums []int) int {
   l, r := 1, len(nums)-1

   for l < r{
       mid := (l+r)>>1
       var count int
       for _, v := range nums{
           if v >= l && v <= mid{
               count++
           }
       }
       if count > mid-l+1{
           r = mid
           continue
       }
       l = mid+1
   }
   return r
}